1. Technical Field of the Invention
The present invention generally relates to audiovisual conferencing. More particularly, the present invention is directed to a system and method for providing a multipoint audiovisual conferencing, which facilitates a dynamically allocated Internet Protocol (i.e., “IP”) address, a dynamically provided Integrated Service Digital Network (i.e., “ISDN”) telephone number (or portion thereof) and a Public Switched Telephone Network (i.e., PSTN) telephone number (or portion thereof) for at least one of the endpoints in an audiovisual conference.
2. Description of the Prior Art
Audiovisual conferencing is increasingly becoming a burgeoning field of endeavor, not only in the high-technology business environment, but also in the field of education (e.g., distance learning), and is steadily picking up speed as it makes its way into the living rooms of households. While engaging a person via voice communication, allows one to exchange ideas with, compel, persuade, challenge or teach the person, projecting a visual representation allows one to magnify the effectiveness of that voice communication.
FIG. 1 is a logical prior art audiovisual conferencing system 100 that depicts a Multipoint Control Unit (i.e., “MCU”) 124 that bridges a plurality of endpoints arriving at the MCU 124 over disparate networks into a multipoint audiovisual conference, which includes two or more endpoints. The H.323 is a standard approved by the International Telecommunication Union (i.e., “ITU”), which defines how audiovisual conference data (i.e., audio, video, data and combination thereof) are transmitted across the disparate networks, including circuit-switched networks and packet-switched networks (e.g., the Internet). Now particularly with reference to FIG. 1, the endpoints 122 represent H.323 terminals that are part of an IP network (e.g., “LAN”) 102 that are routed via router 104 to the MCU 124. Other endpoints may include wireless devices, such a laptop computers 126, wireless telephones 128 and personal digital assistants, (i.e., “PDA”) 129, which are interconnected via a wireless network 108 and interfaced via gateway 106 to the MCU 124. Still other endpoints may include devices 130, 132 and 134 that are respectively interconnected by integrated services digital network (i.e., “ISDN”) 112, public switched telephone network (i.e., “PSTN”) 116 and Enterprise Network 120, which are interfaced to the MCU 124 via respective gateways 110, 114 and 118 and routed to the MCU 124 via routers 104. Endpoints 130 (interconnected via ISDN) and 132 (interconnected via PSTN), utilize the following respective ITU standards H.320 and H.324. As particularly illustrated in FIG. 1, the gateways interface a plurality of disparate networks, such as for example circuit switched networks (e.g., ISDN, PSTN) and packet switched networks, such as the Internet. It is noted that the MCU 124 may include one or more multi-network interfaces for communication with some of the disparate networks. For example, the MCU 124 may include an ISDN interface, in which case the router 104 directly routes the endpoint 130 to the MCU 124, thereby not requiring the gateway 110. Additionally, the MCU 124 may include virtual private network (i.e., “VPN”), asynchronous transfer mode (i.e., “ATM”) and like interfaces for linking the MCU 124 with the disparate networks.
A limitation of the audiovisual conferencing system depicted in FIG. 1 is that bridging via a bridge or MCU 124 is required to interconnect two or more audiovisual conference endpoints depicted in FIG. 1. Bridging is limited because it requires that IP addresses of the endpoints outside the IP network 102 and ISDN/PSTN telephone numbers for the foregoing devices 128, 130 and 132 be known in advance of the audiovisual conference, thereby effectively limiting the audiovisual conference to static IP addresses and telephone numbers for those endpoints. Accordingly, at the time that an audiovisual conference is scheduled, an operator inputs the IP address and telephone number via an input means into the MCU 124, thereby reserving resources and establishing other criteria for the audiovisual conference. The resources may include designation of ports in the MCU 124 and bandwidth for the endpoints and the other criteria may include designation of continuous presence, trans-coding, and the like. A port is a hardware/software device that accommodates a connection of an endpoint to an audiovisual conference. Once a scheduled audiovisual conference takes place, each endpoint involved in the multipoint audiovisual conference must connect or be contacted via the IP address or telephone number provided during scheduling to join the audiovisual conference. However, the foregoing reservation with static IP addresses and telephone numbers represents a significant drawback, since today IP addresses are usually dynamically allocated each time a user signs onto a network, which may be provided by an Internet Service Provider (i.e., “ISP”), and a telephone number for a user's audiovisual conference device (connecting via ISDN/PSTN) may not be known in advance of the audiovisual conference or may change subsequently to the scheduled audiovisual conference. Consequently, an endpoint may not be able to access the scheduled audiovisual conference.
The prior art audiovisual conferencing system 100 of FIG. 1 may further comprise a gatekeeper (not shown), which may be a part of the MCU 124. The gatekeeper is an optional component, which provides functions that preserve the integrity of the IP network 102 for all registered IP endpoints, gateways and multipoint control units within the IP network 102. The gatekeeper provides address translation from aliases for endpoints 122 on the IP network 102 to IP addresses to route video, audio, data and combination thereof, as defined in the registration, administration and status (i.e., “RAS”) specification. The gatekeeper further provides admission control for specifying the endpoints that may establish conferences with other endpoints. Still further, the gatekeeper provides bandwidth management, which is also defined within RAS specification, to manage total bandwidth that is available to the audiovisual conferencing. Finally, the gatekeeper provides zone management for endpoints, gateways and multipoint control units that have registered with the gatekeeper.
A U.S. Pat. No. 6,157,401 to Wiryaman is directed to an endpoint on a common IP network (i.e., Ethernet) initiating a multipoint audiovisual conference by providing aliases for other endpoints to be included in the conference to a gatekeeper located on the Ethernet. It is noted that endpoints that are to be included in the audiovisual conference must beforehand register with the gatekeeper, which manages aliasing for the registered endpoints. It is further noted that the Wiryaman system is a closed system, in which aliases for the endpoints are pre-established and registered with the gatekeeper prior to the conference. Upon connection to the Ethernet, each endpoint's IP address is correlated to the pre-established alias provided to the gatekeeper. However, the Wiryaman system does not address endpoints, which are not registered via the gatekeeper to be able to join in an audiovisual conference. Additionally, if the optional gatekeeper that enables aliasing on an IP network is not provided in the system of FIG. 1, the prior art provides no way for endpoints, whose addresses are dynamically assigned at logon time, to join an audiovisual conference. Consequently, endpoints residing on an Intranet or Internet may not be able to access a scheduled audiovisual conference unless their IP addresses are known in advance of the audiovisual conference.
Therefore there is a need in the art for providing an improved multipoint audiovisual conferencing system and method, which facilitate a dynamically allocated Internet Protocol (i.e., “IP”) address, a dynamically provided Integrated Service Digital Network (i.e., “ISDN”) telephone number and a Public Switched Telephone Network (i.e., PSTN) telephone number for at least one of the endpoints in an audiovisual conference.